Fried Egg PowerBook
Recently, there’s been a lot of feedback and internal discussion around the topic of Powerbook Fever. Phil’s post about using smcFanControl to cool you Mac down solves part of the problem, but Mac OS X in a Nutshell co-author Chris Stone suggests that overheating is often times the result of a runaway process:

Sounds like it’s hung up on some process. What does ‘top -u’ show? The top line of processes there should show what’s chewing up the CPU and causing the fan to stay on. Rebooting would of course clear that up, but if it starts happening again, check with “top”.

It turns out that a runaway application will not only heat up your laptop, but sometimes even prevent it from sleeping correctly. Those of you that know your way around the command line know where to go from here: just open a terminal window and type top -u.

1047 meanapp 99.3% 0:31.09 1 13 16 176K 560K 468K 26.6M
1049 top 14.6% 0:03.55 1 18 20 1.14M 612K 1.61M 26.9M
213 Terminal 0.6% 8:01.23 14 182 239 5.18M- 19.3M- 28.4M- 246M-
282 Safari 0.5% 2:03:22 12 393 2297 218M 81.9M 277M 833M

If you see an application that’s consuming 99% CPU, such as ‘meanapp’ in the above example, it’s probably the cause of your overheating and laptop sleep issues. Scribble down the process ID of the app (in this case 1047), type “q” to exit top, and force the application to quit by typing kill -9 1047, where 1047 is the troublesome process ID.

If this becomes a regular issue, track down the application that’s consistently causing you problems. Chances are it’s a third party application or driver that could use an upgrade.